Diamonds are immensely old and were formed long before dinosaurs roamed the earth. The youngest natural diamond is 900 million years old and the oldest is 3.2 billion years old. Because they are ancient, natural objects, each and every diamond is unique with its own tiny flaws and imperfections. These are frequently invisible to the naked eye and can only be spotted by diamond experts using an eyepiece or microscope. Understanding, however, the global criteria on which diamonds are assessed is a useful starting point in your quest.

 What do I call a Diamond?

 Diamonds, synthetic diamonds and diamond simulants are different products catering to different markets with different value propositions.

A synthetic diamond is an artificial (man-made) product that has essentially the same chemical composition, crystal structure and physical (including optical) properties as a diamond.

A diamond simulant is a product (natural or artificial) that imitates the appearance of a diamond without having its chemical composition, physical properties or structure. Examples are cubic zirconia, moissanite, white sapphire and yttrium aluminium garnet.

Diamond simulants may also include items made from other products or gemstones that have then been coated in synthetic diamond.

The National Association of Jewellers (NAJ) together with eight of the leading diamond industry organisations (AWDC, CIBJO, GJEPC, IDI, IDMA, NDC, WDC and WFDB) endorses the present guideline to encourage full, fair and effective use of a clear and accessible terminology for diamonds, synthetics diamonds and imitations of diamonds by all sector bodies, organisations and traders.

This Diamond Terminology Guideline serves as a reference document for the diamond and jewellery trade when referring to diamonds and synthetic diamonds. It is built on two internationally accepted standards: the ISO 18323 Standard (“Jewellery – Consumer confidence in the diamond industry”) and the CIBJO Diamond Blue Book.

Natural Diamonds

A diamond is a mineral consisting essentially of carbon crystallised in the isometric cubic crystal system, with a hardness on the Mohs scale of 10, a specific gravity of approximately 3.52 and a refractive index of approximately 2.42, created by nature. A diamond always means a natural diamond. 

Synthetic Diamonds

Synthetic diamonds also commonly referred to as laboratory grown diamonds are artificial (man-made) products that have essentially the same chemical composition, crystal structure and physical (including optical) properties as diamonds. 

Stones that might be confused with diamonds

There are a number of synthetic stones on the market that could be confused with diamonds. These are as follows:

• Cubic zirconia (or CZ)
• Zirconium oxide (ZrO2) is a mineral that is extremely rare in nature but is widely synthesized for use as a diamond simulant. This inexpensive, synthesized material is hard, optically flawless and usually colourless although it is also made in a wide variety of different colours.
• Moissanite, which takes its name from the French scientist Dr Henri Moissan who discovered natural moissanite in Arizona in the 1890s, is also known by its chemical name, silicon carbide(SiC). The rarity of natural moissanite crystals large enough for jewellery prohibits their use. For years, scientists tried to re-create this extraordinarily brilliant material. Only recently, through the power of advanced technology has the US company Charles & Colvard, developed a way to produce large gem-quality crystals which can be faceted into near-colourless jewels with real fire and brilliance.
• Diamonique® This is the brand name of a CZ diamond simulant, sold through the internet and television shopping channel QVC.

  How good is your diamond?

A diamond’s value depends on four sets of characteristics – the famous 4Cs which are CLARITY, COLOUR, CUT and CARAT. The first two can be assessed by a skilled person using a universally acknowledged grading system.

Ask for a “Certificate”

Reputable retailers automatically supply customers buying larger diamonds with a certificate, more accurately described as a ‘diamond grading report’. This is your diamond’s own personal passport and is a report of its characteristics and authenticity, but not its monetary value. The report will usually contain information about the clarity and colour grades, plus the shape, weight and measurements of the diamond and a brief assessment of the quality of cut and finish. They will also plot any inclusions and imperfections in your diamond onto a diagram. Any identifying laser inscriptions on the girdle of the diamond may also be described.

What to look for?

There are many people who have been trained to grade diamonds – this is an essential skill for people who make a living from buying and selling diamonds but their grading may not be as reliable as that carried out by a specialist diamond grader working in one of the many independent, certified laboratories around the world offering diamond grading facilities. These bodies will have quality control procedures and grades will be cross-checked by more than one grader who will confirm where your diamond stands in relation to the 4Cs. A reputable diamond retailer will be able to ‘read’ such a report and will be able to explain to you exactly what it means.

Sometimes a jeweller or a customer will ask for a diamond to be graded when it is in its setting in a piece of jewellery – this is clearly less reliable than setting an unset diamond as it is more difficult to view accurately and it cannot be measured or weighed accurately. Look for signs of this in a reduced or shortened report. Some diamond jewellery brands offer their own ‘certificates’ or diamond ‘guarantees’, but if you are spending a large sum of money, you may prefer to ask for an independent assessment of the diamond before you commit to buying it. In some cases, this will require that the stone is removed from its setting. Some of the main bodies offering globally-recognised diamond grading services are:

• The Gemological Institute of America (GIA) - www.gia.edu
• The Gem Testing Laboratory of Great Britain (Gem-A) – www.gem-a.info
• HRD Antwerp NV – www.hrd.be
• Anchor-Cert ® Independent Diamond Certification – www.anchorcert.co.uk

Buy from a reputable source

It pays to go to a reputable and established retailer when buying diamonds. We recommend someone who has real knowledge of diamonds and is a member of a recognised trade association such as the National Association of Jewellers.

Buying diamonds can be complex - remember that when diamonds appear to be offered very cheaply, there are many factors which need to be considered. For a significant purchase, compare the stone with others in a well-lit environment. The fire and sparkle we expect to see from a good quality well proportioned and professionally cut diamond can outshine a larger diamond of poorer quality so decide what is important – a big stone or better quality. Your budget and your own eyes will help you to make the decision.

If you want to buy online and an advertisement refers to clarity, colour and weight, it is reasonable to ask about the cut quality. Check also whether the grading has been carried out by a reputable laboratory and do not be afraid to use your right to return under the distance selling regulations, remembering that you must send the item back within seven working days of receiving it.

Above all – do your homework, trust your eyes and be happy with your diamond!

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Originally Published - https://www.naj.co.uk/advice/buying-diamonds